Anaphylactic Shock

Dear Dr. B: What is anaphylaxis?

Anaphylaxis (say “anna-full-ax-iss”) is a life-threatening allergic reaction. It occurs when a person becomes sensitized to a substance and is again exposed to that substance.

The body responds with release of histamines and other substances into the bloodstream. This results in dilated blood vessels and swollen tissues. Swelling of the tongue and throat may be life-threatening if obstruction of the airway occurs, if blood pressure drops, or if cardiac rhythm becomes abnormal.

Reaction starts soon after you are exposed to something you are severely allergic to. There may be swelling, itching or a rash. You may have trouble breathing, with a tight feeling in the chest or dizziness. You may feel anxious. There may be stomach cramps, nausea or diarrhea. Some people lose consciousness.

There are many causes of anaphylaxis. Here are few examples:
-Foods, such as shellfish, nuts, peanuts, eggs and fruits
-Medicines, such as antibiotics, aspirin, over-the-counter pain relievers, allergy shots and contrast dye for radiologic procedures
-Latex or rubber found in surgical gloves, medical supplies and many products in your home
-Insect stings, especially from bees, wasps, hornets, yellow jackets, sawflies and fire ants

A severe allergic reaction requires immediate treatment. If anaphylaxis is suspected then check the airway for tongue swelling or swelling of the soft palate or uvula. Check the blood pressure and the pulse. Low blood pressure and rapid pulse raises the suspicion of anaphylaxis, although neither is necessary for diagnosis.

Certain individuals are at a high risk of fatal anaphylaxis. These are the individuals who have had previous severe reaction to a substance, leading to progressive reaction and asthma. Certain medications may increase the risk because some agents like aspirin, non-steroidal anti-inflammatory drugs like Ibuprofen, beta-blockers and ACE inhibitors are well known to intensify reactions.

Once anaphylaxis is diagnosed, epinephrine should be injected immediately by intramuscular route. It should injected into the muscles of your arm are thigh. Epinephrine will quickly raise the blood pressure by constricting the blood vessels, it will increasing the heart rate, reduce swelling around the face and throat and relax smooth muscles in the lungs to make breathing easier. CPR may become necessary. This will allow time to call 911 and transport the patient to the nearest hospital for further stabilization and treatment.

Epinephrine is available as an auto-injector. That means you can inject it yourself or your friend or family member can inject it for you if you are having a severe allergic reaction. There are two kinds of auto-injectors: EpiPen and Twinject. EpiPen has one dose of epinephrine and Twinject has two doses of epinephrine. If symptoms do not subside within 10 minutes of the first injection then second dose of epinephrine is required. This happens in 35 per cent of people with severe allergic reaction.

It is very important to learn how to use the auto-injector. It is of no good use to carry one in your pocket or purse if you do not know how to use it. Also check on the expiry date. These auto-injectors have a short expiry date of a year or so. Replace expired auto-injectors. Wear a medical alert bracelet or necklace. Also carry antihistamine like Benadryl with you which is helpful in case of a mild allergic reaction.

As always, prevention is better than treatment. See a doctor to identify the causative agent of your allergy. It is not always easy to find the causative agent as we come in contact with numerous substances each day. If the causative agent is known then avoid it at all cost. Ask your doctor if you need desensitization shots. Make sure people around you – your family, friends, teachers, co-workers and others are aware of your allergy. Live a normal life but be careful of what you eat and what you touch.

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